Acute changes of left atrial distensibility in congestive heart failure.
BACKGROUND
Investigations of the left atrial (LA) distensibility have revealed that it plays a major role in atrial function; however, LA distensibility has not as yet been studied in congestive heart failure (CHF).


OBJECTIVE
The study was undertaken to determine the effects of acute administration of esmolol, isosorbide dinitrate, dobutamine, and normal saline infusion on LA dimension, pressure, and distensibility.


METHODS
The study included 23 patients with CHF (18 with ischemic heart disease and 5 with idiopathic dilated cardiomyopathy). Left atrial diameters (D) and pressures (P) were recorded at rest and thereafter during acute tests. P and D data during the ascending limb of the V loop were fitted to the exponential function P = b.ead, where a is the passive elastic chamber stiffness constant and b is the elastic constant. The instantaneous diastolic LA distensibility (IDLAD) was calculated as 1/(dP/dD) = 1/a.P.


RESULTS
The constant, a, increased significantly after normal saline and esmolol infusion (p < 0.001), while it significantly decreased after isosorbide dinitrate (p < 0.001) and dobutamine administration (p < 0.05) compared with baseline. Instantaneous diastolic LA distensibility (in mm/Hg) was 0.16 at baseline; it significantly increased after isosorbide dinitrate (0.32) and dobutamine (0.24) administration, while it significantly decreased after normal saline (0.11) and esmolol (0.12) infusion (p < 0.001 for all).


CONCLUSIONS
In CHF, LA distensibility may acutely increase with vasodilators or inotropics or may decrease with beta blockade or volume loading.
Dernellis
J M
JM
First Cardiology Department, Amalia Fleming Hospital, Athens, Greece.
Vyssoulis
G P
GP
Zacharoulis
A A
AA
Toutouzas
P K
PK
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D006328:Cardiac Catheterization; D002311:Cardiomyopathy, Dilated / Q000150:complications; D004280:Dobutamine / Q000008:administration & dosage; D004452:Echocardiography; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D006333:Heart Failure / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007548:Isosorbide Dinitrate / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications; D011237:Predictive Value of Tests; D011412:Propanolamines / Q000008:administration & dosage; D014665:Vasodilator Agents / Q000008:administration & dosage
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D014665:Vasodilator Agents; D004280:Dobutamine; D007548:Isosorbide Dinitrate; C036604:esmolol